The past is another country.
From 1943: “Kill Or Be Killed”, a short film explaining in no uncertain terms that there are no rules of sportsmanship on the battlefield.
Bonus video #1: “Don’t Kill Your Friends”, also from 1943. I’m pulling this one out because…well…you’ll see less than 30 seconds in.
“…he’s not so much a name, as a state of mind.” Truer words were never spoken, about both the movie character and his namesake.
Bonus video #2: “Shoot To Kill”. This is actually a British Army training film, about the proper use (and effective ranges) of various issue weapons, including the Bren gun and anti-tank rifles.